Ibn Taymiyyah said that there are three ways of employing Jinns:

1-      Employing them in impermissible acts, which is, of course, not allowed.

2-      Employing them in permissible acts, for example, fetching one's money. This type is permissible.

3-      Employing them in  good acts; meaning, ordering them to obey Allaah The Almighty and the Prophet, sallallaahu ‘alayhi wa sallam , just like ordering humans to obey Allaah The Almighty and the Prophet, sallallaahu ‘alayhi wa sallam. By doing so, a person would be following the guidance of the Prophet, sallallaahu ‘alayhi wa sallam, and his followers from among the Ummah (Muslim nation) - who are the best of mankind.

In conclusion, employing Jinns is permissible when they are employed in permissible acts, and vice versa. So it should be investigated how the Jinn would be employed in the process of Ruqyah: If the jinn is assigned to bring medicine or the like, it would be permissible. If  they were employed to do an  impermissible act, such as sorcery, this would be impermissible.  

At the same time, it is better not to deal with the Jinn at all. One should not seek their help and should not have any confidence in them. In fact, one should not speak with them at all. Dealing with Jinns may bring about some unforeseen evil consequences.

The best course of action is that exemplified by the Prophet, sallallaahu ‘alayhi wa sallam, and his Companions . It was not narrated that any of them sought the help of a Jinn in Ruqyah, in fetching lost items, nor in seeking protection from harm.

Allaah Knows best.